Styrene!-acrylonitrile! graft copolymer on rubber-elastic polymer - is pptd. continuously from dispersion and sintered in three-zone tubular reactor

摘要

A dispersion of styrene-acrylonitrile graft copolymer on a rubber-elastic polymer and a pptnt. are introduced into the pptn. zone of a tubular reactor comprising a pptn. zone, a sintering zone and a discharge zone. The reactor contains rotating supply- and mixer-units and its length: dia. ratio is 10:50. The tempo. is 20-150 degrees C in pptn. zone, 80-240 degrees C in sintering zone and o0-180 degrees C in discharge zone, provided that in sintering zone the temp. is kept at 30-90 degrees C above the temp. in pptn. zone and in discharge zone, the temp. is kept at 30-120 degrees C below the temp. in sintering zone. Average polymer dwelling time in reactor is 0.5-10 mins. Dwelling time in each of pptn.-, sintering- and discharge zone is 1/5 to 1/2 of total dwelling times and the dwelling times in the zone add up to 1. The pressure in pptn. - and sintering-zones corresponds to the liq. phase vapour pressure at the prevailing temp. The total liq. and polymer phase vol. is 10-100% of the free reactor vol. Finally, the liq. phase and sintered polymer mixt. is discharged through the discharge zone. The particles obtd. are used as additives to improve the toughness of styrene-acrylonitrile polymers. The polymer dispersion is self-sealing so that sintering zone pressure can lie above surrounding pressure without the need for a pressure-valve.